This was the main continuation from this opening, although it is
now considered pretty played out. Black has a bad bishop on c8,
so...

12... e5 13. dxe5 Nxe5 14. Nxe5 Qxe5 15.
f4

Black has a choice of several queen moves. In the
first game we examine what happened after 15...Qe7 [next
diagram]

White has the better bishop, currently pointed at Black''s King's
side, but this is only a temporary advantage. Left alone, Black can
play ...Be6 or move the b-pawn and play ...Bb7. White's only hope
of a win is to keep Black on the hop.

16. f5

Stops ...Be6 well enough, but Euwe has further plans for
this pawn - namely, to run it to f6, disrupting the K-side and
using the good bishop for attack.

Bs move on squares of only one colour. A bishop hemmed in by its
own pawns on the same colour squares is called a bad
bishop. It is sometimes tempting to put pawns on the same
colour squares as the bishop, particularly in the ending, with the
hope that the bishop will defend them. Well, unfortunately, the
bishop will probably be so blocked by the pawns that it can hardly
defend itself. Depending on what other pieces there are on the
board, the opponent's king will probably be able to slip in between
the pawns, and the bishop won't be able to stop it. You want your
pawns on one colour square, and the bishop on the other, in the
middle game and in the ending. (And if you've got two bishops in
the middle game, you generally want your pawns right out of the
way.) So be careful where you put your pawns, and don't get your
bishops stuck one side or the other of a chain of pawns.

-- Alexander Alekhin, on the advantage of the Two Bishops at
amateur level

The bishop is a longer-range piece than the knight. This
advantage is sometimes called the minor exchange, for, all else
being equal, the bishop will be a better piece than the knight. Two
bishops, provided they can make use of their better range and
aren't blocked by pawns, are rather better than two knights or a
knight and a bishop, particularly in fully open positions. (Think
how easy it is to mate with the two bishops. Have you ever tried to
mate with two knights?)

Capablanca advised rehearsing the mate with the two
Bishops, not because it was particularly likely to occur in
practice, but to experience directly the power of two Bishops
cooperating in an open position.

So in OPEN positions, the two bishops are boss.

In CLOSED positions, the knights may be better.

In SEMI-OPEN positions. well...

The side with the two bishops must not let the knight(s)
settle on any outposts, and can create trouble on both sides of the
board at once when the poor knights will be hard-put to keep up.
It's generally though that the two bishops are good enought to win.
Paulsen made use of this in the middle 1800s, but the technique was
perfected and publicised by Steinitz.

It's worth dwelling on this for a moment. Material is
equal, and Black can think about getting his own majority moving,
but its all too late. The two bishops cover all the key squares,
and Black can hardly stop the advance of the a-pawn.

Here is an instructive moment from the Nunn/Griffiths book. White
has many advantages, including an extra pawn.

25. Nf5!

"White is still in no hurry to exchange queens: he
permits his opponent the option of 25...Bxf5 26 Qxf5 instead of the
game continuation. EITHER WAY HIS BISHOP-PAIR WILL DOMINATE THE
BOARD. But he is also returning the extra pawn: possibly as
instructive a piece of Grandmaster thinking as anything that has
gone previously. The point is not that the variations are difficult
to calculate, but that Nunn is thinking boldly; dynamically. Time
and again we see how his thinking is the reverse of a weaker
player. It is not, 'If I play Nf5 I shall lose a pawn; I will only
do that as a last resort'; but rather, 'I can simplify the position
by Nf5 and continue to generate powerful threats; it would be a
miracle if Black could get away with ...Rxc2"

Black is doing his best to get White to play d4-d5, when as well
gaining the square c5, Black would expect the blocked pawn
formation to favour the Knights. White finds an interesting way of
resisting the encouragement.

This leap into the (still) empty d5 point provokes Black into
giving up the remaining Bishop. It should not be supposed that
Golombek was unaware of the dangers in this, but considered it
relatively best, given the pressure on f6. 20... Bxd5 21.
cxd5 c6 22. Qb3 Kh8 23. Rae1 h6 24. Qa3 g5 25. Bg3 Nd7 26. dxc6
Nxc6 27. Bb5

After the pins on the King's-side have finally been disposed of,
White starts up in the same trade on the Queen's-side!

27... Rxf1+ 28. Rxf1 Ncb8

this decentralising move doesn't look right

29. Bc4 Rf8

Black's position now falls apart

30. Rxf8+ Qxf8 31. dxe5 Nc5 32. exd6
Nxe4

[Have the Knights finally secured a
defence?]

33. d7 ! 33... Nc5

[33... Qxa3 34. d8=Q+ Kg7 35. Qg8+ Kf6 36.
Qf7#]

34. Be5+ Kh7 35. Bd3+

Golombek comments that these weren't mere Bishops, but Archbishops!
1-0

Normally in the Nimzo-Indian Defence, Black hopes to
double the c-pawns to give a target for attack in the event that
White disappears off to the King's side. Not here, so Black can
only hope to gum up the game for his knights.

Chess Quotes

"The technician, whose vocabulary has been doubled by Dr. Euwe, will find that White could have saved his soul by a desperado combination. Had this failure anything to do with the fact that Dr. Euwe's terminology was not yet existent at that time!?"